The Combustion Core will provide critical support by providing consistent, reproducible, well-characterized surrogates of combustion-generated ultra-fine and fine particle/pollutant systems for study in the biomedical and non-biomedical projects. It consists of two facilities, a thermal reactor laboratory and a pilot-scale rotary kiln combustion facility. The thermal reactor laboratory will prepare samples of ultra-fine and fine particle/pollutant systems that have been synthesized using chemical and thermal techniques. It will generate size-selected/controlled surrogates of combustion-generated particles consisting of particles of silica doped with metal nanoclusters and organic pollutants. A high-temperature flow reactor can be used to generate entrained metal nanoparticles as well as soot-coated nanoparticles. This reactor system can be interfaced directly to animal exposure chambers. A well-developed dosing procedure will be used to introduce desired pollutants and control whether they are physisorbed or chemisorbed to the particles, as well as whether or not free radicals are formed. The rotary kiln facility can be used to scale up these processes to produce pollutant/particle systems formed under near 'real-world' conditions and perform treat ability studies of actual Superfund site waste materials. Both the rotary-kiln and thermal reactor can be used to simulate soils contaminated with hazardous waste that have undergone thermal treatment. In conjunction with the Analytical Core, this core will provide detailed characterization of each type of sample through techniques including EPR for persistent free radicals, high resolution electron microscopy for particle size and morphology, GC-MS for organic adsorbates, XPS for metals, and XANES/EXAFS for organic metal bonding. In the past year, techniques have been developed and demonstrated for the generation and characterization of each type of pollutant/particle system that will be used in this program. We have recently developed methods for convenient synthesis of size-controlled particles containing Fe and Ni in addition to Cu. This core will work closely with Project 1 to develop additional methods for nanoparticle synthesis and characterization and provide gram-scale quantities of highly-characterized, reproducible, laboratorygenerated surrogates of combustion-generated pollutant/particle systems to each of the projects. These pollutant/particle systems can be custom synthesized to facilitate testing of specific hypotheses.